Refillable fuse plug



Dec. 15, 1936. G. E. RUDNICK REFILLABLE FUSE PLUG Filed March 28, 9 5

Q INVENTOR 7 BY 6AM Zia aw Jfid A TTORNEY Patented Dec. 15, 1936 UNITED STATES PATENT OFFICE 1 Claim.

My invention relates to improvements in reflllable fuse plugs.

It relates particularly to fuse plugs of the cartridge type in which a replaceable fuse strip extends through an insulating tube and has its ends removably clamped between conductive end members on the tube.

One of the objects of my invention is to provide a refillable fuse plug of the kind described, which may be easily and quickly refilled when the fuse burns out; which will provide secure and good contact engagement of the fuse with the conductive end members; which will hold the intermediate portion of the fuse from contact with the insulating tube; which is novel, cheaply made and is efiicient in its operation.

The novel features of my invention are hereinafter fully described and claimed.

In the accompanying drawing, which illustrates the preferred embodiment of my invention,

Fig. 1 is a side elevation of my improved fuse plug, showing one of the end caps in the removing and inserting position, and showing the other end cap in the fuse clamping position.

Fig. 2 is a longitudinal central section of what is shown in Fig. 1.

Fig. 3 is a side elevation of the fuse plug shown in Fig. 1, partly broken away, with the left end cap in the removing position, and the right end cap removed.

Fig. 4 is a side elevation of the fuse plug shown in Fig. 1, with the end caps both in the clamping position.

Fig. 5 is an enlarged section on the line 5--5 of Fig. 1.

Fig. 6 is an enlarged section on the line 6-6 of Fig. 1.

Fig. 7 is an enlarged section on the line 1-1 of Fig. 4.

Fig. 8 is a side elevation of the fuse plug shown in Fig. 1, with the end caps removed.

Fig. 9 is a perspective view of one of the end caps shown in Fig. 1.

Fig. 10 is a longitudinal section of the same before the end plate of the cap is flattened.

Fig. 11 is a longitudinal section of what is shown in Fig. 10 with the end plate flattened.

Figs. 12 and 13 are side elevations of my improved fuse plug provided with knife blade contacts on the end caps.

Similar characters of reference designate similar parts in the different views.

I designates a tube of insulating material having at its respective ends two alined recesses 2. 3 designates two collars of conductive material which respectively tightly embrace the end portions of the insulating tube I, and which are respectively provided with end slots 4 which register with the recesses 2, and which are formed by cutting from the outer ends of the collars 3 respectively two tongues 5 which are extended inwardly from the inner ends of the slots 4 through the recesses 2, the inner end portions of the tongues 5 being preferably bent at angles toward the opposite ends respectively of the tube l, as best shown in Fig. 2.

6 designates a flat strip fuse of usual type, the end portions of which extend from inside the tube I over and against the tongues 5 and through the recesses 2 and slots 4 and respectively upon the outer sides of the collars 3, Figs. 2 and 5 to 8.

Respectively removably slidably and rotatably fitted on the collars 3 are electrically conductive end members, preferably of cap form, as shown, and comprising each a tubular cylindrical body 1 having at one end an inner annular flange 8 against which tightly bears an end plate 9. If desired the end plate 9 could be omitted.

Each body 1 is provided with a T-shaped slit having a longitudinal stem I0 extending from the open end of the cap, and a transverse portion II at the inner end of the portion l0 thus forming two clamping lips at opposite sides of the stem 10.

At the inner side of the slot 4 each collar 3 is provided with an even, smooth unbroken annular portion upon which snugly fits the body I of the adjacent end cap, when the fuse 6 is not lying on said annular peripheral portion.

When the fuse 6 is inserted through the tube 1, the caps being removed, the end portions of the fuse are passed through the recesses 2 and slots 4 and upon the annular even peripheral portions of the collars 3. The caps are then slipped over the collars 3 with the longitudinal slits l0 alined with the fuse 6, as in the cap at the left in Fig. l. The fuse 6 causes the clamping lips at opposite sides of the slit portions 10 of the caps to expand and the fuse to be tightly clamped between the caps and the smooth peripheral portions of the collars 3. Due to the slit portion ll extending circumferentially at opposite sides of the slit portion ID of each cap, the lips will exert a substantially even pressure over their inner surfaces.

The caps are then rotated on the collars 3 to positions in which the slit portions of the caps will be out of alinement with the fuse, thereby increasing the clamping effect of the caps upon the fuse B and collars 3, and holding the cap reliably from accidental removal from the operative clamping positions.

When a fuse burns out the caps are retracted to the positions in which the slits Ill aline with the fuse, after which the caps may be withdrawn from the collars 3 and the burned out fuse removed and a new one substituted therefor, after which the operation of replacing the end caps on the collars is repeated.

In the making of each cap, the end plate 9 thereof is slightly cupped, as is shown in Fig. 10. When the end plate is flattened, as shown in Fig. 11, it will be held firmly in its operative closing position.

For use where knife blade contacts are required, each end plate 9 of each cap may have riveted, or otherwise centrally secured to it a conductive blade [2, as shown in Figs. 12 and 13.

With the employment of the tongues which hold the fuse at its intermediate portion from contact with the insulating tube I, the heat developed in the fuse will not be absorbed by the tube, as such absorption might interfere with the proper operation of the fuse. The tongues 5 being in the recesses 2 also serve to hold the collars 3 from turning on the tube I when the caps are revolved to more tightly clamp the fuse 6, thus avoiding liability of severing the fuse.

With the provision of the T-shaped slits in the bodies 1 of the end caps, the latter, although snugly fitted to the collars 3, when the fuse is not disposed thereon, may be readily slipped onto and off from the collars, when the slits l0 allne with the fuse and the latter is disposed on the annular even perhipheral portions of the collars. By then revolving the caps on the collars, the fuse is very firmly clamped in its operative position.

Many modifications of my invention, within the scope of the appended claim, may be made without departing from the spirit of my invention.

What I claim is:-

In a fuse plug, a tube of insulating material having in one end a recess, an electrically conductive collar embracing said end and having a slot registering with said recess and a tongue extending from the inner end of said slot through said recess and beyond the inner wall of said tube, and an annular resilient electrically conductive member slidable and revoluble on said collar and removable therefrom and having extending from its inner end a longitudinal slit terminating in a transverse slit which extends circumferentially in opposite directions from said longitudinal slit, thereby forming two clamping lips adapted to be expanded by said collar and to tightly clamp against said collar a removable fuse adapted to be extended longitudinally through said tube and against said tongue and through said slot and recess and onto the periphery of said collar.

GEORGE E. RUDNICK. 

